Vesper,
Here is a screenshot of my batch file...
For all your batch files: Leave the shaders flag off, as you should only use it or thread-concurrency but not both (using TC overrides shaders). I would remove temp-target as you're specifying 100% fans, so there's no need for a target.
For my scrypt kernel file: Try changing your gpu_engine to 1000, also try 1100, (and steps inbetween by factor of 15, 1015, 1030, etc) as those two are the stock clocks for the gigabyte. I'm hoping that works for you.
I would also play around with the scan-time flag, maybe upping it (unless forums have directed you otherwise with that card). I go with the default 60, I'm not sure if going up or down will provide any benefit, but once you have a stable hashrate it can't hurt to experiment a little.
A quick question on riser cables... I need PCI-E 16x to PCI-E 16x... do I need/want powered riser cables?
You don't need a powered riser. It won't hurt to have one, but in my experience there's no use for one. I believe BitcoinExpress has the same opinion. These systems are designed to draw the majority of their current through the PCIE power jacks. The PCIE-cable-provided power is for the logic controls.
Can I use a PCI-E 1x to 16x riser cable going from a 16x slot to the GPU? The interwebs seem to indicate that I can... can you confirm?
Yes you can use a 1x just fine. For the purposes of mining, these systems only use the 1x factor for data transmission. I have a couple of 1x-16x extensions and they're working fine.
Also power supplies... I am using Antec Truepower Classics 750W for my 2x280X miners... is that enough... thinking that I should move up to 850W PSU... if so what brand and model?
Also thinking of building my first 3x280X rig... what is your preferred PSU?
For longevity definitely go for anything 1100watts or above for 3 (1200+ ideal), or at minimum, 1050watts if the 12v rail is 29-30amps (per gpu).
For my R9 280x test rig, I have a 1050watt delivering around 27amps per GPU, running 2 MSI and 1 Toxic R9, and it's definitely being maxed out. I just ordered some 1100watt PSUs to try out, they deliver 30amps per GPU (more current on the PCIE than the one I have). The important part is making sure each GPU can get 300watts of power (25amps), but realistically they draw 325-350 (27-29amps) if you're pushing them hard. 350*3=1050 for just the GPUs, not counting motherboard or other items.
If all else fails I'll mix 2 R9 cards with 1 7950 card and the new 1100w PSU, if I can't run 3 R9 cards on it.
I have to be honest, EarthCoin is going to my coin of choice in the long-term as it fits our business model with the farm much better, but that is not taking anything away from the TAG team and their coin, which I still believe has the most concentrated, focused and funded admin and development team of any coin. TagCoin was born for a purpose, which sets it in a league of it own to begin with.
OT, but those veggies look tasty. Makes me want to fly down there and eat some
I'm confident tagbond will get things going, sometime this year. I do still mine other coins however, as my plan is simple: mine anything which comes along and store up some of it, and dump most of the goofy coins while they're valuable (dogecoin for example) to pay for the electric bills.
Because you never know what coin is going to really take off next. This is why I believe altcoins even have value (people trading BTC for Scrypt coins).. everyone wants to have pieces of the pie.